Hard to tell from your screencast alone, as you don't have construction history exposed, HIK panel doesn't help much.
Does traditional (from the Shelf or the Menu) Extrude behave similarly?
I usually struggle to remember to disable this Shift-extrusion, as it might happen accidentally, thus I have no positive xp with it.
In any case, the screencast shows many seemingly irrelevant hotkeys pressed, check if those aren't damaged.
Also, it might not be enough to just delete the construction history, which still is the safest way to restore tools expected functionality. Check the geo on its integrity Mesh>Cleanup, as with too sensitive hotkeys you can run into non-manifolds pretty rapidly.
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Maya2019.1 @ Windows10 & GeForce GTX1080Ti
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